> old enough to have made presentations with transparent sheets on an overhead projector I’m in my early thirties and we sometimes used transparent sheets on o

> old enough to have made presentations with transparent sheets on an overhead projector I’m in my early thirties and we sometimes used transparent sheets on overhead projector too when I was in school. Although in our case we made the sheets with the computer (Microsoft Word, Paint, etc) and they gave us transparent sheets that we put in the printer. I remember that the ink on the transparent sheets would smudge if we touched it, which sometimes accidentally happened when we handled our transparent sheets. Even in high school I sometimes saw teachers use overhead projection with transparent sheets. One of my math teachers in high school brought a special device with him one day. This one https://www.calculatorsource.com/ti-89titanium-vs.html https://www.calculatorsource.com/ti-89titanium-vs.html (or some other model by TI). It’s an external screen that you connect to a TI graphing calculator and then put it on top of the glass plate of an overhead projector so that you can project what the calculator is showing for everyone to see :)